Three optical remote-sensing system types — distinguished by how much of the spectrum they sample and how finely:

• Multispectral — a few (5–15) discrete broad bands covering visible → SWIR. Example: Landsat TM/ETM+, SPOT, IKONOS.
• Thermal — one or more bands in the thermal-IR region (8–14 µm). Example: Landsat TIRS, ASTER thermal.
• Hyperspectral — hundreds of narrow contiguous bands (5–10 nm each). Example: Hyperion on EO-1 (220 bands, 0.4–2.5 µm).

Reference: Jensen, 2000.